* Work by delegates on new global climate deal continues (Adds detail, quotes)

By Susanna Twidale and Nina Chestney

WARSAW, Nov 21 (Reuters) - Around 800 people from environmental groups, including Greenpeace and WWF, walked out of U.N. climate talks in Warsaw on Thursday in protest at what they see as a lack of progress towards a global deal to curb greenhouse gas emissions.

It is the first time green groups have staged such a coordinated walkout at U.N. climate talks and could further dent public perceptions of the effectiveness of the Warsaw conference.

"This does not affect the work going on behind closed doors but it certainly won't help people's perceptions at home of what we are trying to do here," a U.N. delegate who wished to remain anonymous told Reuters.

More than 9,000 representatives from about 195 countries are gathered in the Polish capital for a two-week conference working towards a pact to be signed in 2015 to curb rising greenhouse gas emissions, to come into force after 2020.

But the talks, ending on Friday, have stuttered over several issues, particularly whether rich nations should pay developing countries for losses suffered due to the effects of climate change, and the lack of ambitious pledges to cut emissions.

U.N. Secretary-General Ban Ki-moon urged world leaders on Thursday to make "bold pledges" for emissions cuts in greenhouse gases by next September but acknowledged that many nations would be late.

He also said rich nations' promises in Warsaw for new funds to help the poor tackle more heatwaves, floods and rising sea levels caused by global warming were "insufficient".

"Warsaw has simply not been good enough," said Kumi Naidoo, executive director of Greenpeace International.

"We believe in this process. We will never give up on it because people around the world desperately need a global treaty on climate change. But a new treaty must also be meaningful."

FRUSTRATION

Green groups said they were frustrated with the lack of strong leadership from developed nations, particularly Poland, which is hosting the talks.

Marcin Korolec, who is chairing the negotiations, was dismissed as Poland's environment minister on Wednesday in a Polish government reshuffle.

Although he remains in charge of the conference, the move has raised doubts over Poland's position in the negotiations. Some delegates at the talks said it indicated that Poland was not interested in ensuring tougher global action to combat global warming.

Poland's decision to host a coal industry summit alongside the climate talks on Monday and Tuesday had also angered many non-governmental organisations (NGOs).

"This is one of the most 'captured' summits ever - by corporates and coal industry with the support of the Polish government," said Dipti Bhatnagar at Friends of the Earth International.

"We are walking (out) to send a strong message due to the total inaction at the talks, due to lack of ambition and finance, at a time when we need the most action."

The U.N.'s climate chief, Christiana Figueres, insisted work at the conference continued.

"Everybody is working very hard; everybody is working through the night; there is nobody here who is lazy," U.N. climate chief Christiana Figueres told Reuters.